In the telecommunications industry, there is a market segment known as Enterprise Networks (EN) referring typically to a large-scale network for a large enterprise and connecting many components or networks such as LAN's, WAN's and other applications and components. Most of the products manufactured to serve this market are powered from commercial utility AC power lines. This electrical power is an alternating current/voltage and is supplied at 115 VAC in the United States and at 230 VAC in most parts of the rest of the world. In order to market EN products in the international market, it is desirable that each product be capable of operation from either 115 or 230 VAC utility line input voltage without any manufacturing or customer involvement.
Electronic circuits in the EN equipment use direct current/voltage (DC) to operate and this power should be supplied to the electronic circuits at a constant non-varying DC level. In order to accommodate the DC voltage requirements of these electronic circuits, a power supply operates as a power converter that is typically incorporated into the EN equipment to convert the higher utility line AC voltage to the lower DC voltage. The power supply handles the two different input voltage levels supplied from the utilities in order to provide the proper power. One method currently used by power supplies connects a programmable rectifier circuit to the AC utility input. The rectifier has a high voltage DC output of approximately 310 VAC. It is programmed and configured as a voltage doubler when the input is 115 VAC and programmed and configured as a full wave bridge rectifier when the input is 230 VAC. It would be advantageous to perform automatic utility line voltage selection and programming, however, and permit control circuit latching or locking of the rectifier circuit in the programmed state.